Short Message Service (SMS) is warmly welcome by users of mobile phones. An advantage of SMS over the conventional Call Service is that a sender may much less worry about receipt of a message. Even if a receiving terminal is turn-off or in a place having weak signals, the message will be finally received when the user turns on his mobile phone or goes into a place having strong signals. However, in regard to the conventional Call Service, most users had such an experience that a calling signal can not be received or the speech quality is degraded if the intensity of signals is low in situ. In this situation, the receiver will not obtain the information unless a communication connection is re-established between the pair in the places having strong signals. It further goes without saying that no calls will be received when a receiving terminal is turn-off. Another advantage of SMS is its low service fee.
At the early stage of the development of SMS, a short message only comprises text content without any multimedia information, such as melodies and pictures, so that the message contains a small amount of information and thus can be consisted of one transport protocol data unit (TPDU). SMS protocol supports the transmission of such a short message. Recently, Enhanced Short Message Service (EMS) is introduced in the recommendation of mobile SMS 3GPP TS 23.040. An EMS possibly contains a lot of information and requires more than one TPDU. The present protocol also supports the transmission of an EMS in network by concatenating several TPDUs.
However, the present protocol does not guarantee that the concatenated TPDUs arrive at a terminal in order. Not only the TPDUs from one EMS may arrive at the terminal in disorder, but also the TPDUs from different EMSs may arrive interleavingly. For example, two EMSs are sent to a terminal. One is consisted of 4 concatenated TPDUs in the order of m1, m2, m3 and m4, and the other is consisted of 5 concatenated TPDUs in the order of M1, M2, M3, M4 and M5. As the protocol does not support the arrival of the TPDUs in order, they may arrive at the terminal in the following order of m4, m1, M3, m2, M5, M2 . . .
As EMSs may arrive at a terminal in disorder, several problems issue and need to be solved. The first problem is when the user is notified of arrival of an EMS. One simplified contemplation is to notify the user when all the TPDUs arrive. As is well known, one or more TPDUs of an EMS could be lost in the period of transmission. Therefore, in this contemplation, if one of the TPDUs never arrives, a man-machine interface (MMI) will not be connected with a application layer of an open system so that the user will neither be notified of arrival of an EMS nor be able to lookup any content of the EMS. Another consideration is to notify the user of arrival each time when one TPDU arrives. However, sometime, this method will burden the terminal and disturb the user too much.
Another design is contemplated by notifying the user of arrival of an EMS and displaying its content on a screen when all the TPDUs arrives in correct order, and displaying incorrect content (for example, displaying in disorder) on the screen when the EMS arrives in disorder or at least one TPDU is lost. Although, the third design still notifies the user of arrival of an EMS even if one TPDU never arrives, the EMS is simply displayed by incorrect content on the screen. It is neither friendly to the users nor reasonable to the user interface.
Therefore, another problem arises, i.e. how to recognize and display individual TPDUs which arrive at the terminal in disorder?
Still another problem is how to present a “broken” EMS. Here, the term “broken” means that the EMS is not completed with one or more TPDUs missing.
Therefore, there exists a need to provide a improved method for managing a concatenated Enhanced Short Message at a telecommunication terminal in order to notify the user of arrival of the message at proper time and display the content of the received EMS reasonably and friendly.
Accordingly, an object of the invention is to provide a method for managing a concatenated Enhanced Short Message at a telecommunication terminal.
Another object of the invention is to provide a method for notifying an user of arrival of an EMS.
Still another object of the invention is to provide a method for displaying an EMS in user friendly way.
Further another object of the invention is to provide a telecommunication terminal using the inventive method for managing a concatenated Enhanced Short Message.